A quarter of the UK and Ireland's puffin population live on the archipelagoReuters

The National Trust of Scotland (NTS) is launching a funding drive to help with costs to maintain and preserve the UK's only dual world heritage site: the islands of St Kilda. One of the most remote parts of the UK, the islands have not been permanently inhabited since 1930.

According to NTS, St Kilda is home to Europe's largest colony – over a million – of nesting seabirds. This includes a quarter of the UK and Ireland's Atlantic puffins.

The islands are hard to reach, with no scheduled ferries – visitors have to go on day trips with particular companies. The islands' last 36 inhabitants were relocated at their own request in 1930 after the tough way of life had become unsustainable.

St Kilda is only place in the UK, and one of few in the world, that has joint status as a natural and cultural heritage site – the 32 others that enjoy this label include the Tasmanian wilderness in Australia and Mount Athos in Greece.

St Kilda is an archipelago consisting of a large island, Herta, and three smaller islands, Soay, Boreray and Dun. Though not permanently inhabited, conservation workers, scientists and some military personnel are stationed there.

The islands are owned by the NTS and, according to The Guardian, cost £270,000 ($395,000) a year to conserve. Recent studies have suggested that the biggest threat to the seabird population on the islands is climate change.

Rising sea temperatures force fish to move to cooler waters, leaving the seabirds with food stocks further afield from traditional nesting grounds. Last year, the NTS shockingly recorded that the population of black-tipped kittiwakes on St Kilda has fallen by 90% in 15 years – with only one chick born on the island in 2015.

The St Kilda field mouse is thought to have originally arrived with the vikings over a thousand years ago. Now, allegedly thanks to a lack of predators on the islands, they have grown to twice the size of their predecessors.

The NTS has been in charge of St Kilda's conservation for 60 years, they said: "Now, 86 years after the last native St Kildans left, new threats are on the horizon. It's our mission to make sure the cultural heritage they left behind, and the outstanding natural heritage, isn't lost too."